(1)
Each
product sterilizer shall be equipped with at least one mercury-in-glass
thermometer or an equivalent temperature-indicating device.

(2)
Mercury-in-glass thermometers shall have
divisions that are easily readable to one degree Fahrenheit and whose
temperature range does not exceed seventeen degrees Fahrenheit per inch of
graduated scale.

(3)
Thermometers
and temperature-indicating devices shall be tested for accuracy against a known
accurate standard thermometer upon installation and at least once a year to
ensure their accuracy.

(4)
A
thermometer that has a divided mercury column or that cannot be adjusted to
essential agreement with the standard shall be repaired or replaced.

(5)
Thermometers and temperature-indicating
devices shall be installed where they can be accurately and easily read.

(6)
The temperature-indicating
device shall be the reference instrument for indicating the processing
temperature.

An accurate temperature recorder-controller shall be located in
the product sterilizer at the final heater outlet. It shall be capable of
ensuring that the desired product sterilization temperature is maintained. The
chart graduations shall not exceed two degrees Fahrenheit within a range of ten
degrees Fahrenheit of the desired product sterilization temperature.

When a product-to-product regenerator is used to heat the cold
unsterilized product entering the sterilizer by means of a heat exchange
system, it shall be designed, operated, and controlled so that the pressure of
the sterilized product in the regenerator is greater than the pressure of any
unsterilized product in the regenerator.